Traditionally shower pans used in shower stalls are installed on top of a bathroom subfloor. As is typical, shower pans of all types, whether prefabricated or custom configured for a particular space, comprise a surface that is gently sloped towards a drain outlet. The need for a slope and the thickness of the materials comprising the shower pan have a distinct thickness. Further, especially in the instance of a custom shower pan, finish flooring material is installed on top of the shower pan surface adding additional thickness.
Because of the added thickness of the shower pan over the surrounding bathroom floor, there usually must be a lip at the intersection of the pan with the surrounding floor to both provide for a visual transition for a shower user and to contain water from the shower in the stall. These lips can detract from the aesthetics of a shower stall, and even more significantly hinder access to and from the shower by the disabled and elderly.
While processes for recessing the subfloor of a bathroom in the region over which a shower pan is to be installed are known, they are usually very labor intensive, and accordingly expensive. Furthermore, if the recessed subfloor is not properly installed, which typically comprises wood bracing and blocking, the load carrying capacity of the recessed floor might not be adequate to handle the loads incident on it.